1. Field of the Invention
The present invention relates to a sheet sorting and storing apparatus. More particularly, the present invention relates to a sheet sorting and storing apparatus having a plurality of bin trays for consecutive reception of sheets discharged from an external apparatus like an image forming apparatus such as a copier.
2. Description of the Related Art
In some conventional sheet sorting and storing apparatus, a spacing between bin trays is enlarged upon sheet discharge to facilitate sheet storage. For example, Japanese Unexamined Patent Publication Sho 57-4855 discloses a sheet jogger/sorter using a Geneva wheel to open a spacing between a determined bin tray and the next upper bin tray to readily receive a discharged sheet thereon. Further, Japanese Unexamined Patent Publication Sho 5678769 discloses an improved sorter using a helical cam to similarly open a spacing between bin trays.
Another type of conventional sorter is one which does not open spacing between bin trays to facilitate the sheet reception. For example, Japanese Unexamined Patent Publication Hei 2110075 discloses a sorting apparatus using a cam in connection with vertical motion of parallel bin trays to move a desired bin tray for receiving a discharged sheet so as to form a sheet reception entrance without opening the spacing between the bin trays.
In the apparatus of the former type which opens the bin tray spacing upon sheet reception, a room for sheet storage may be saved because the bin trays are held at a normally unenlarged bin tray spacing except the sheet receiving bin tray. It is, however, required that a mechanical structure using a Geneva wheel or a helical cam be used in the mechanism for the space opening, which is disadvantageous with respect to a smooth space opening operation. Also, offensive shock noises cannot be avoided in such a mechanism upon the spacing opening operation.
In the latter device, the spacing between the bin trays is always kept constant, so that a space opening mechanism is unnecessary and noises may be reduced. It is, however, difficult for such a mechanism to produce a sufficient sheet receiving entrance size, causing a problem of sorting or receiving a sheet when bent or curved. Furthermore, if a substantial number of sheets are expected to be stored on the bin trays, all the spacings between the bin trays must be enlarged, which results in increase in scale of the apparatus. This increase in size of the apparatus is contrary to the desire of downsizing. Therefore, the latter mechanism includes an inherent disadvantage to realize both downsizing and sufficient storage amount of sheets.